The Sandwich Generation don't truly exist in the English-speaking West. The situation only happens when an Immigrant joins the West bringing their culture which conflicts with the Western Culture. This isn't a debate of what is right or what is wrong, but what we are required to do or not to do.
Most Asians born in the West have no obligations as an Asian. They are not Asian, they've never been to Asia. Their family is Westernized. However, those people ALWAYS wants benefits. Unless you are in Asia and the benefits is for you, there is no obligation to PROVIDE benefits to others that have used all the benefits for themselves.
You need to seek counselling if you feel you need to take care of your parents. That's what doctors are telling you, and me.